There are steering apparatuses that in order to make it possible to adjust the forward-backward position of a steering wheel comprise a telescopic function that is constructed by a steering column having an outer column and an inner column that are fitted together so that sliding movement is possible in the axial direction. Moreover, there are also steering apparatuses that comprise a shock absorbing function that, during a collision accident of a vehicle, is able to protect the driver by allowing the steering wheel to displace in the forward direction while at the same time absorbs an impact load that is applied from the driver during a secondary collision that occurs following a primary collision in which an automobile collides with another automobile or the like, when the driver collides with the steering wheel. In a steering apparatus that comprises a telescopic function and an impact absorbing function, there is construction as disclosed in WO 2009/013457 (A1) in which together with forming a slit in the axial direction of the outer column, a clamp apparatus that expands or contracts this outer column in the width direction and an operation lever that operates this clamp apparatus are provided, and by operating this operation lever, the diameter of the outer column is contracted, and by tightly fastening the outer circumferential surface of the inner column to the inner circumferential surface of the outer column, it is possible to clamp the inner column to the outer column so that relative movement in the axial direction is not possible.
In a steering apparatus with a telescopic mechanism, by operating the operation lever in the opposite direction, the tight fit of the outer column around the inner column is released, and then by expanding or contracting the entire steering column by sliding the outer column with respect to the inner column, the forward-backward position of the steering wheel can be adjusted. However, in a steering apparatus with a shock absorbing function, during normal operation, the outer column is supported by a vehicle-side bracket that is supported by the vehicle body, however, during a secondary collision, due to an impact load that is applied to the outer column, the outer column is able to displace in the forward direction by breaking away from the vehicle-side bracket, while an energy absorbing member that is provided between the outer column and the vehicle side absorbs the impact load.
However, in the steering apparatus having the construction disclosed in WO 2009/013457 (A1), one end of the slit in the outer column is open to the end surface in the axial direction of this outer column. Therefore, depending on the position in the forward-backward direction of the steering wheel, the distance between the closed end section on the other end of the slit and the clamped position of the outer column changes. Therefore, even though the diameter of the outer column is contracted by a specific force using the expansion and contraction mechanism, depending on the position in the forward-backward direction of the steering wheel, there is a problem in that the clamping force of the outer column on the inner column fluctuates.
In a steering apparatus that is disclosed in JP 2002-274393 (A), a distance bracket (column-side bracket) that is divided into two parts is arranged so as to face both sides in the width direction of the steering column, and by directly clamping the outer circumferential surface of the inner column with one distance bracket, the clamping force of the outer column on the inner column does not fluctuate depending on the forward-backward position of the steering wheel.
However, in the construction disclosed in JP 2002-274393 (A), the outer circumferential surface of the outer column is clamped by one distance bracket, ant the outer circumferential surface of the inner column is clamped by the other distance bracket. Therefore, only the outer circumferential surface on one side in the width direction of the inner column is clamped, so there is a problem in that the balance on the left and right of the clamping force is bad. Moreover, each of the two distance brackets is supported so as to be able to pivot around a pin, so there are problems in that construction of the distance bracket is complicated, and the manufacturing cost increases.
Furthermore, in a steering apparatus disclosed in JP 5-262238 (A), the inner column is directly clamped by a pressure piece that is supported by the distance bracket so as to be able to slide. In the construction disclosed in JP 5-262238 (A) as well, the outer circumferential surface of the inner column is clamped on only one side by one pressure piece, so there is a problem in that the balance on the left and right of the clamping force is bad. Moreover, the pressure piece is a separate part from the distance bracket and is supported by the distance bracket so as to be able to slide, so there are problems in that construction is complicated, and the manufacturing cost increases.
The contents of WO 2009/013457 (A1), JP 2002-274393 (A) and JP 5-262238 (A) are incorporated in this specification by reference.